For semiconductor devices, for example power semiconductor devices, compound semiconductors such as III-V compound semiconductors have become more and more important in recent years, since they allow for semiconductor devices with higher doping and shorter drift zone compared to silicon-based semiconductor devices while retaining a high blocking capability.
Up to now, power semiconductor devices based on III-V compound semiconductors are realized as lateral devices. These devices are known as high electron mobility transistors (HEMTs). An HEMT includes several layers of differently doped semiconductor materials with different band gaps. Due to the different band gaps of the individual layers, a two-dimensional electron gas (2DEG) is formed at the interface of these layers, the two-dimensional electron gas serving as a conductive channel. The mobility of the electrons as well as the 2D-electron charge carrier density is very high in the two-dimensional electron gas.
The two-dimensional electron gas is provided in a region between a source electrode and a drain electrode. When the HEMT is used as a switch, e.g., as a switch for inductive loads, various operation modes such as turn-off of inductive loads come up. An HEMT that meets demands on a switch operating in various modes is desirable.